Side entry mufflers include a muffler shell with an exhaust inlet positioned in the muffler shell between opposing shell ends. The exhaust inlet includes an extrusion that provides a connection interface for an exhaust inlet pipe. Typically, this extrusion extends outwardly from an outer shell surface and is formed with a press and die apparatus. A die is positioned against the muffler shell at a desired exhaust inlet opening position and a press applies pressure at a die and muffler shell interface to form the extrusion.
The use of this press and die method has several disadvantages. One disadvantage is that the extrusion must be formed in the muffler shell before internal muffler components, such as baffles, support tubes, etc. can be stuffed into the muffler shell. This requirement interrupts flow along a muffler production line. Any interruption in material or component flow on a high speed production line significantly increases cost. On a high speed production line for side entry mufflers, the muffler shell is first formed from shell blanks. Once formed, the muffler shell is moved offline to a press and die arrangement to form the extrusion for the exhaust inlet. The muffler shell is then returned to the production line to receive the internal muffler components. Due to this interruptive production process, this type of muffler configuration has traditionally only been used for low volume muffler lines that are dedicated to a single product.
Another disadvantage with extrusions formed with a press and die arrangement is material thinning. A base radius area of the extrusion has a tendency to thin out during pressing. This thinning at the base radius area reduces extrusion durability performance.
Thus, there is a need for a process for making a side entry exhaust inlet extrusion that can be incorporated into a high speed production line, and which has improved extrusion durability characteristics, as well as overcoming the other deficiencies with prior designs described above.